Bronchial hyperresponsiveness

Bronchial hyperresponsiveness (or other combinations with airway or hyperreactivity) is a state characterised by easily triggered bronchospasm (contraction of the bronchioles or small airways).

Bronchial hyperresponsiveness can be assessed with a bronchial challenge test. This most often uses products like methacholine or histamine. These chemicals trigger bronchospasm in normal individuals as well, but people with bronchial hyperresponsiveness have a lower threshold.

Bronchial hyperresponsiveness is a hallmark of asthma but also occurs frequently in people suffering from chronic obstructive pulmonary disease (COPD).^[1] In the Lung Health Study, bronchial hyperresponsiveness was present in approximately two-thirds of patients with non-severe COPD, and this predicted lung function decline independently of other factors.^[2] In asthma it tends to be reversible with bronchodilator therapy, while this is not the case in COPD.

Bronchial hyperresponsiveness has been associated with gas cooking among subjects with the GSTM1 null genotype.^[3]

Footnotes

↑ Postma DS, Kerstjens HA (November 1998). "Characteristics of airway hyperresponsiveness in asthma and chronic obstructive pulmonary disease". Am. J. Respir. Crit. Care Med. 158 (5 Pt 3): S187–92. doi:10.1164/ajrccm.158.supplement_2.13tac170. PMID 9817744.
↑ Tashkin DP, Altose MD, Connett JE, Kanner RE, Lee WW, Wise RA (June 1996). "Methacholine reactivity predicts changes in lung function over time in smokers with early chronic obstructive pulmonary disease. The Lung Health Study Research Group". Am. J. Respir. Crit. Care Med. 153 (6 Pt 1): 1802–11. doi:10.1164/ajrccm.153.6.8665038. PMID 8665038.
↑ Amaral, A. F. S.; Ramasamy, A.; Castro-Giner, F.; Minelli, C.; Accordini, S.; Sorheim, I.-C.; Pin, I.; Kogevinas, M.; Jogi, R.; Balding, D. J.; Norback, D.; Verlato, G.; Olivieri, M.; Probst-Hensch, N.; Janson, C.; Zock, J.-P.; Heinrich, J.; Jarvis, D. L. (10 March 2014). "Interaction between gas cooking and GSTM1 null genotype in bronchial responsiveness: results from the European Community Respiratory Health Survey". Thorax 69 (6): 558–564. doi:10.1136/thoraxjnl-2013-204574.

Respiratory physiology

Respiration	positive pressure ventilation breath (inhalation exhalation) respiratory rate respirometer pulmonary surfactant compliance elastic recoil hysteresivity airway resistance bronchial hyperresponsiveness bronchoconstriction/Bronchodilatation

Control	pons pneumotaxic center apneustic center medulla dorsal respiratory group ventral respiratory group chemoreceptors central peripheral pulmonary stretch receptors Hering–Breuer reflex

Lung volumes	VC FRC Vt dead space CC PEF calculations respiratory minute volume FEV1/FVC ratio methods of lung testing spirometry body plethysmography peak flow meter nitrogen washout

Circulation	pulmonary circulation hypoxic pulmonary vasoconstriction pulmonary shunt

Interactions	Perfusion (V) ventilation (V) ventilation/perfusion scan zones of the lung gas exchange pulmonary gas pressures alveolar gas equation alveolar–arterial gradient hemoglobin oxygen–haemoglobin dissociation curve (Oxygen saturation 2,3-BPG Bohr effect Haldane effect) carbonic anhydrase (chloride shift) oxyhemoglobin respiratory quotient arterial blood gas diffusion capacity (DLCO)

Insufficiency	high altitude oxygen toxicity hypoxia

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